| From: | Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> |
|---|---|
| To: | Thibaut Madelaine <thibaut(dot)madelaine(at)dalibo(dot)com>, Yuzuko Hosoya <hosoya(dot)yuzuko(at)lab(dot)ntt(dot)co(dot)jp>, "'Imai, Yoshikazu'" <imai(dot)yoshikazu(at)jp(dot)fujitsu(dot)com> |
| Cc: | "'PostgreSQL Hackers'" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Problem with default partition pruning |
| Date: | 2019-03-25 00:21:06 |
| Message-ID: | fa6ba10b-2123-22b6-8888-e6a3ec84101a@lab.ntt.co.jp |
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| Lists: | pgsql-hackers |
Hi,
On 2019/03/23 2:36, Thibaut Madelaine wrote:
> I tested your last patch and if I didn't mix up patches on the end of a
> too long week, I get a problem when querying the sub-sub partition:
>
> test=# explain select * from test2_0_10 where id = 25;
> QUERY PLAN
> ------------------------------------------------------------
> Seq Scan on test2_0_10 (cost=0.00..25.88 rows=6 width=36)
> Filter: (id = 25)
> (2 rows)
The problem here is not really related to partition pruning, but another
problem I recently sent an email about:
https://www.postgresql.org/message-id/9813f079-f16b-61c8-9ab7-4363cab28d80%40lab.ntt.co.jp
The problem in this case is that *constraint exclusion* is not working,
because partition constraint is not loaded by the planner. Note that
pruning is only used if a query specifies the parent table, not a partition.
Thanks,
Amit
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